Shelters, shacks, & shanties The classic guide to building wilderness shelters
SHRC SHELTERS - Oklahoma State University–Stillwater · 2020-01-31 · shrc shelters staci...
Transcript of SHRC SHELTERS - Oklahoma State University–Stillwater · 2020-01-31 · shrc shelters staci...
SHRC SHELTERSSTACI CUCCIO, FLINT HOLBROOK, KEVIN ROEWE, & JARED SWART
MISSION
• Create safe economical shelter designs
• Design outstanding features
• Satisfy client & market demands
PROBLEM STATEMENT
• Storm shelter production for A-1 Blasting,
Inc. of Broken Arrow, Oklahoma
• Market analysis
• Engineering design
• Projected cost & sales
STATEMENT OF WORK
• Competitive advantages
• Standards & specifications research
• SolidWorks shelter designs
• Potential alternative functions
• Production costs
FALL SEMESTER TASKS LIST
• Research patents
• Research testing/certification
• Analyze market
• Design basic shelter
• Consider multiple usages of shelter
• Determine construction materials
• Perform detailed engineering analysis of forces
• Draw detailed design in SolidWorks
• Estimate costs
SPRING SEMESTER TASK LIST
• Prototype chosen by A-1 Blasting, Inc.
• Potential to build prototype
• Test prototype
• Create marketing materials
STANDARDS & SPECIFICATIONS
• National Storm Shelter Association
• ICC-500
• FEMA P-361
• Texas Tech University Certification
DESIGN REQUIREMENTS
• Designed to meet FEMA P-361
requirements for intense wind event
• Multiple requirements
WIND LOADING - WALL SECTION
𝑊𝑖𝑛𝑑 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑙𝑏
𝑓𝑒𝑒𝑡2 = 0.00256 ∗ 𝑊𝑖𝑛𝑑 𝑠𝑝𝑒𝑒𝑑 𝑚𝑖𝑙𝑒𝑠
ℎ𝑜𝑢𝑟
2
• Rated for winds perpendicular to the
face of the wall
• Gusts last for three seconds
• Designed for max gust of 250 mph
http://www.bdcnetwork.com/appcenter/wind-load-shear-wall-design-calculator
FLYING DEBRIS• Most dangerous characteristic of a tornado
TEXAS TECH UNIVERSITY WIND
SCIENCE & ENGINEERING
RESEARCH CENTER• Tests projectile impact on structures
• Uses a standard 15 lb 2”x4”
• Speeds of up to 100 mph horizontally
• Speeds of up to 67 mph vertically
• Creates a momentum force on cross-
sectional area of 68 lbf/s
• Energy on impact of 5,017 ft-lb
DOOR FRAME & DOOR
• Requires five 3/8” lag screws in door jam &
three in head
• Steel door composed of 14 gauge steel or
stronger
• Attached to a solid frame at six points
- Three points on latch side
- Three points on hinge side
• Three contact points on each side
ANCHOR SYSTEM
• Determined by the size of shelter
• Must be of sufficient tensile strength
http://www.confast.com/products/thunderstud-anchor.aspx
VENTILATION
• Apply by local jurisdiction
• Two possible locations
• Vertical is best
• Protection
• For residential shelter, 2 in2 per person
MORE REQUIREMENTS
• Amount of time for occupancy
• Wall height specification
• Recommended area per occupant
ENGINEERING DESIGNS
Concrete StructureSteel Structure
ENGINEERING
• Blowing away
• Uplift
• Frame deformation
• Perforation
• Plate deformation
BLOW AWAY
• Wind Pressure [psf] =
0.00256 ∗ Velocity [mph]2
= 0.00256 ∗ (250 mph)2
= 160 psf
• Wall force = Wall area ∗ Wind Pressure
• Force = 8’ ∗ 8 ’ ∗ 160 psf = 10,240 lb
• 1,280 lb force per foot of wall width
BOLT INFORMATION
• 3/8” Grade 2 Bolt:
Ultimate tensile strength = 74ksi
• Shear strength = 0.60 ∗ Tensile strength
= 0.60 ∗ 74 ksi = 44.4 ksi
• Bolt area = (Design factor ∗ Force) / Stress
= 2∗1280 lb
44400 psi= 0.0577
in2
ft wall width
• Bolt diameter = 0.0577 ∗4
π= 0.271 inches
FEMA P-361 Figure 4-3: ROOF UPLIFT PRESSURES
UPLIFT CALCULATIONS
• Edge Force = Edge Area ∗ Edge Pressure
= 238 psf ∗ 44 ft2 = 10,472 lb
• Corner Force = Area ∗ Corner Pressure
= 4 ft2 ∗ 396 psf = 1,584 lb
• Total Force = Edge + Corner Uplift Forces
= 10,472 lb + 1,584 lb = 12,056 lb
UPLIFT
• Hold Down Force =Uplift Force − Shelter Weight= 12,056 lb − 2,000 lb = 10,056 lb
• Bolt Stress =Force
Area=
Total Force
Total Bolt Area
=10,056 lb
25 ∗π4∗
38in
2 = 3,642 psi (tension)
• Approximately 402 lb per bolt
FRAME INERTIA
Moment of Inertia = 0.650 in4
FRAME DEFORMATION
• Double 2” x 4” stud wall
– E ∗ I = 17.15 million lb*in2
• 2” x 3” x 3/16” angle iron
– E ∗ I = 19.5 million lb*in2
• Steel is approximately 14% stronger
• Surpasses the double stud wall structure
PERFORATION
• FEMA P-361 Section 7.3.2 states:
“In laboratory tests at Texas Tech University, 12-
gauge or heavier steel sheets have never been
perforated with the 15 lb wood 2”x4” traveling at
100 mph.”
• 10 gauge steel sheets used for the
remainder of the design work
PROJECTILE ENERGY
• Kinetic Energy = 0.5 ∗ Mass ∗ Velocity2
=0.5∗15lb∗(100 mph)2 = 75,000 lb-mph2
• KE = 75,000 lb-mph2 = 5,015 ft-lb
(FEMA P-361 Table 7-2)
• 9 lb 2”x4” at 128 mph 4,932 ft-lb
(FEMA P-361 Table 7-2)
IMPACT FORCE
• 5,015 ft-lb 60,180 in-lb (2) = 120,360 in-lb
(Design Factor = 2)
• Force = Energy / Distance
• Force = 120,360 in-lb / 3 in = 40,120 lb
• Impact Force = 40,120 lb
PLATE DEFORMATION
• Deflection = Force∗Max Radius2/(16∗π∗D)
• D =𝐸∗𝑡3
12∗ 1−𝑣 2 =(30∗106 𝑝𝑠𝑖)∗0.1345 𝑖𝑛3
12∗ 1−0.3 2
• D = 12,414 in-lb
• Deflection = 40,120 𝑙𝑏∗ 6 𝑖𝑛 2
16∗𝜋∗12,414 𝑖𝑛 𝑙𝑏= 2.315 in
FINAL STEEL DESIGN
• 2” X 3” X 3/16” angle iron 12” o.c.
• 10 gauge sheet metal skin
• 3/8” anchor bolts 12” o.c. around perimeter
• Steel entry door
– 14 gauge skin
– 20 gauge reinforcement
– 6 points of contact
FINAL CONCRETE DESIGN
• Vertical Walls– 6” concrete
– #4 rebar spaced 12” horizontally & vertically
• Roof– 4” concrete
– #4 rebar spaced 12” horizontally & vertically
• Steel entry door – 14 gauge skin
– 20 gauge reinforcement
– 6 points of contact
MARKET TRENDS
• Highly fragmented industry
• Small private businesses with alternative revenue streams
• $21 million per year, thirteen firms reporting
• Average price same over last five years, due to recession & depressed material prices
• Moves with housing starts
• Housing starts expected to increase over next five years
COMPETITORS• Direct Competitors: Above ground shelters
– Mostly above ground steel
– Most are tremendously over designed
– Varying prices & sizes
• 4.5’ x 2.5’ $2900
• Propane tank $3200
• 6’ x 8’ $5000
– Most are sold for garage installation
• Indirect Competitors: Underground
shelters
CONCEPT & VALUE PROPOSITION• FEMA P-361 standards
• Three sizes– 3’ x 4’ x 8’
– 5’ x 6’ x 8’
– 6’ x 8’ x 8’
• Finished interior
• Seamless integration
• Easy build-in
• Target new homes
• Priced less than competitors
OPERATION DISTRIBUTION
• Homebuilders as distributors
• Homebuilders pick up shelters from A-1
Blasting, Inc., install & finish
• Homebuilder can include storm shelter in
price of home
• A-1 Blasting, Inc. does not need
installation equipment or sales staff
–Leverage risk reduction
PRICING
Concrete Steel Concrete Steel Concrete Steel
3’x4’ 3’x4’ 4’x6’ 4’x6’ 6’x8’ 6’x8’
Costs:
Material $1188.50 $1553.26 $1312.22 $1864.61 $1477.00 $2277.48
Labor $713.10 $192.70 $787.332 $287.58 $886.20 $454.82
Variable
Costs$1901.60 $1745.96 $2099.55 $2152.19 $2363.20 $2732.30
CM at
50%$950.80 $872.98 $1049.78 $1076.10 $1181.60 $1366.15
Price $2852.40 $2618.94 $3149.33 $3228.29 $3544.80 $4098.45
TULSA VOLUME PROJECTIONS
Projected
Year 2012 2013 2014 2015 2016
Number of
New Homes4,382 4,746 5,128 5,526 5,940
Market Share 0.40% 1.00% 1.50% 2.20%
Projected
Sales19 51 83 130
MARKETING PLAN
• Marketing Materials
– Brochures
– Mailings
– Video
• Relationship Building
– Five largest homebuilders initially
• Local Tradeshows
FINANCIAL HIGHLIGHTS
• $57,000 in sales & $8,000 profit in 2013
• Five year average revenue growth of 186%
• $580,000 in sales & $87,000 profit in 2017
P/E of 24
Valuation $2.1 million
ACKNOWLEDGEMENTS
• Bob Smith & A-1 Blasting, Inc.
• Dr. Paul Weckler
• Dr. James Hardin
• Win Adams
QUESTIONS?